Accelerated aging test method for checking forward pressure-bearing life of interlayer of double-pulse engine

Abstract

The invention relates to an accelerated aging test method for examining the forward pressure-bearing life of a double-pulse engine interlayer, which comprises the following steps of: carrying out a thermal accelerated aging test on an interlayer material to obtain an aging model of the interlayer material, and further calculating an acceleration coefficient relative to a working temperature at an aging temperature. And calculating the acceleration time of the interlayer at the aging temperature according to the estimated service life and the acceleration coefficient. And a thermal accelerated aging test is carried out on the interlayer, and production, matching and final assembly of the double-pulse engine interlayer forward pressure-bearing test engine are completed. And carrying out double-pulse engine interlayer forward pressure-bearing test engine ground test run, and determining whether the interlayer can meet the forward pressure-bearing life requirement or not according to the test run result. According to the method, the forward pressure-bearing life of the interlayer can be efficiently, quickly and intuitively assessed.

Description

Technical Field

[0001] This invention relates to an accelerated aging test method for assessing the positive pressure bearing life of the interlayer of a dual-pulse engine, and belongs to the field of dual-pulse solid rocket motors. Background Technology

[0002] The axial and radial partitioned dual-pulse solid rocket motor mainly consists of a single pulse propellant grain, a single pulse ignition device, an axial and radial partition, a second pulse propellant grain, a second pulse ignition device, and a nozzle.

[0003] The working principle of an axial + radial partitioned dual-pulse solid rocket motor is as follows: After receiving the ignition command, the engine ignites and initiates the first pulse. The engine shuts down after the first pulse fuel is exhausted. During the operation of the first pulse combustion chamber, the axial + radial partitions must maintain structural integrity. After a few seconds, a second pulse is randomly initiated via program control. The exhaust gas generated by the second pulse ignition opens the axial + radial partitions in the reverse direction. The engine shuts down again after the second pulse fuel is exhausted. The materials, structural form, and operating mode of the first and second pulse propellant grains of the dual-pulse engine are basically the same as those of conventional engines, and its lifespan is likely not significantly different from that of conventional engines.

[0004] However, the separator layer is crucial for isolating the high-temperature, high-pressure combustion gases during the first pulse of the propellant. Its ability to maintain this isolation capability after long-term storage is critical for axial and radial isolation dual-pulse engines. If the separator layer fails to withstand the pressure of the first pulse of combustion gases after aging, premature combustion of the second pulse will occur, leading to engine failure. Therefore, it is necessary to assess the separator layer's ability to withstand the pressure of the first pulse of combustion gases after aging. However, assessing the separator layer's pressure-bearing performance through natural storage presents challenges such as excessively long testing cycles and high development costs. Therefore, accelerated aging methods are needed to evaluate the separator layer's pressure-bearing life, which can significantly shorten the testing cycle and reduce development costs.

[0005] After a novelty search, no publicly available reports were found in domestic or international literature that are closely related to an accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine's interlayer. Summary of the Invention

[0006] The technical problem solved by this invention is: to address the issue of the positive pressure bearing performance of the partition in an axial + radial double-pulse solid rocket motor, an accelerated aging test method is provided to assess the positive pressure bearing life of the partition in a double-pulse motor. This method can efficiently, quickly, and intuitively assess the positive pressure bearing life of the partition.

[0007] The technical solution of this invention is:

[0008] An accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine's interlayer includes:

[0009] Thermal accelerated aging tests were conducted on the interlayer material to obtain an aging model of the interlayer material.

[0010] Calculate at aging temperature T a Below the operating temperature T s The acceleration coefficient r;

[0011] Based on the estimated lifespan and acceleration factor r, the aging temperature T of the interlayer is calculated. a acceleration time t a ;

[0012] The interlayer was subjected to accelerated thermal aging test;

[0013] Completed the positive pressure test of the dual-pulse engine compartment, engine production, component assembly and final assembly;

[0014] A ground test of the engine was conducted to perform a positive pressure test on the partition of the dual-pulse engine. Based on the test results, it was determined whether the partition could meet the positive pressure life requirements.

[0015] Furthermore, the step of conducting accelerated thermal aging tests on the interlayer material to obtain an aging model of the interlayer material specifically involves:

[0016] Based on accelerated testing of the interlayer material, the aging model for obtaining the sensitive parameters of the interlayer material conforms to the following formula, where the sensitive parameter is elongation;

[0017] K = Ze -E / RT

[0018] In the formula: K is the aging rate constant; Z is the pre-exponential factor; E is the aging activation energy; R is the molar gas constant; T is the aging temperature.

[0019] Furthermore, the calculation of the acceleration factor at the aging temperature relative to the operating temperature is specifically as follows:

[0020] Typical engine operating temperature T s Then the interlayer material in T s Lower aging rate constant K s For formula

[0021]

[0022] Under the premise of ensuring the time, select aging temperature T. a Then the interlayer material in T a Lower aging rate constant K a For formula

[0023] The interlayer material at aging temperature T a Lower relative operating temperature T s The acceleration coefficient r is given by the formula

[0024]

[0025] Furthermore, the calculated interlayer at aging temperature T a acceleration time t a Specifically:

[0026] Assuming the engine's estimated lifespan is t years, and the separator's lifespan should be no less than t years, then the separator at aging temperature T... a acceleration time t a For formula

[0027] Furthermore, a thermally accelerated aging test was conducted on the partition layer, specifically by placing the partition layer in a high-temperature insulation chamber for t a The temperature of the insulated box is set to T. a After completing the thermal accelerated aging test of the interlayer, the interlayer is removed.

[0028] Furthermore, the dual-pulse engine partition positive pressure test engine includes: a single-pulse ignition device, a double-pulse ignition device, a test container, a dummy charge, a pressure measuring connector, a partition, a transition section, a standard gas generator, and a nozzle;

[0029] The cavity inside the test container is filled with dummy drug, and a spacer is bonded to the top end of the dummy drug and the inner surface of the columnar hollow structure. One end of the transition section is fixed to the test container with bolts, pressing the spacer tightly, and the other end is fixedly connected to a standard gas generator with bolts. The standard gas generator is filled with real drug and is used to provide a pressure environment for isolating positive pressure conditions. The nozzle is connected to the standard gas generator with bolts. The single-pulse ignition device and the double-pulse ignition device are both connected to the test container with threads.

[0030] During the interlayer margin test, the dummy drug is first loaded into the test container. After the dummy drug has completely solidified, the interlayer is bonded to the top end face and the inner surface of the columnar hollow structure of the dummy drug. Then, the transition section and the test container are connected by bolts. Then, the standard gas generator and the nozzle are connected in sequence by bolts. Then, the pressure sensor is installed on the pressure measuring bracket. Finally, a single-pulse ignition device and a double-pulse ignition device are installed, and the test can be carried out.

[0031] During the test, the first pulse ignition device works first, spraying out a high-temperature, high-pressure gas jet to ignite the propellant in the standard gas generator. The standard gas generator continues to work until the end. The integrity of the partition and whether the gas generated by the standard gas generator enters the surface of the fake drug through the partition can be determined by the pressure sensor on the first and second pulse ignition devices and the pressure sensor connector.

[0032] Furthermore, the completion of the dual-pulse engine partition positive pressure test engine production, matching and final assembly specifically includes:

[0033] First, a dummy drug is placed in the test container. After the dummy drug has completely solidified, a partition layer is bonded to the top end face and the inner surface of the columnar hollow structure of the dummy drug. The transition section and the test container are then bolted together. Then, the standard gas generator and the nozzle are connected in sequence with bolts. Subsequently, a pressure sensor is installed on the pressure measuring socket. Finally, a single-pulse ignition device and a double-pulse ignition device are installed to carry out the test.

[0034] Furthermore, the ground test of the engine undergoing the dual-pulse engine partition positive pressure test specifically includes:

[0035] During the ground test of the engine to conduct a positive pressure test of the interlayer, the first pulse ignition device was activated first, spraying a high-temperature, high-pressure gas jet to ignite the propellant in the standard gas generator. The standard gas generator operated until the end. The pressure during the first pulse operation can be obtained from the pressure measuring hole on the first pulse ignition device. The pressure in the second pulse chamber during the first pulse operation can be obtained from the pressure measuring hole and the two pressure sensors on the pressure measuring connector of the second pulse ignition device.

[0036] Furthermore, comparing the results of the two-pulse pressure with the one-pulse pressure, if there is a situation in the two-pulse pressure that is not much different from the one-pulse pressure, that is, the difference does not exceed 0.5MPa, then it is considered that the interlayer structure is damaged during the one-pulse operation, and the interlayer cannot meet the positive pressure bearing performance requirements after aging for t years; otherwise, it is considered that the interlayer can meet the positive pressure bearing performance requirements after aging for t years.

[0037] The advantages of this invention compared to the prior art are:

[0038] (1) This test method can greatly shorten the natural storage time of the interlayer by using thermal accelerated aging.

[0039] (2) The test engine used in this test method can directly borrow the I and II pulse ignition devices of a full-size engine. After the test is completed, a new standard gas generator and ignition device can be installed to conduct the test again, which greatly reduces the development cycle and cost. Attached Figure Description

[0040] Figure 1This is a schematic diagram of the interlayer margin test apparatus; Detailed Implementation

[0041] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0042] To conduct accelerated aging tests to assess the forward opening life of the dual-pulse engine's diaphragm, this invention uses, as follows: Figure 1 The partition margin test apparatus shown serves as a test engine for the positive opening of the partition in a dual-pulse engine. The apparatus includes a single-pulse ignition device 1, a double-pulse ignition device 2, a test container 3, a dummy charge 4, a pressure measuring connector 5, a partition 6, a transition section 7, a standard gas generator 8, and a nozzle 9.

[0043] The test container 3 is made of 30CrMnSiA steel. The cavity inside the test container 3 is filled with dummy drug 4. A spacer 6 is bonded to the top right end face and the inner surface of the columnar hollow structure of the dummy drug 4. One end of the transition section 7 is fixed to the test container 3 with bolts, which compresses the spacer. The other end is fixedly connected to the standard gas generator 8 with bolts. The standard gas generator 8 is filled with real drug and is used to provide a pressure environment for isolating positive pressure conditions. The nozzle 9 is connected to the standard gas generator 8 with bolts. The first pulse ignition device 1 and the second pulse ignition device 2 are both connected to the test container 3 with threads.

[0044] During the interlayer margin test, the dummy drug 4 is first placed into the test container 3. After the dummy drug 4 has completely solidified, the interlayer 6 is bonded to the top right end face and the inner surface of the columnar hollow structure of the dummy drug 4. Then, the transition section 7 and the test container 3 are connected by bolts. Next, the standard gas generator 8 and the nozzle 9 are connected in sequence by bolts. Then, a pressure sensor is installed on the pressure measuring connector 5. Finally, the I pulse ignition device 1 and the II pulse ignition device 2 are installed to carry out the test. During the test, the I pulse ignition device 1 works first, spraying a high-temperature, high-pressure gas jet to ignite the propellant in the standard gas generator 8. The standard gas generator continues to work until the end. The integrity of the interlayer 6 and whether the gas generated by the standard gas generator 8 enters the surface of the dummy drug 4 through the pressure measuring holes on the I pulse ignition device 1 and the II pulse ignition device 2, as well as the pressure measuring connector 5, can be determined by the pressure sensors.

[0045] The accelerated aging test method for assessing the positive opening life of the diaphragm in a dual-pulse engine, proposed in this invention, includes the following steps:

[0046] Thermal accelerated aging tests were conducted on the separator material to obtain an aging model, and the acceleration coefficient relative to the operating temperature at the aging temperature was calculated. Based on the estimated lifespan and the acceleration coefficient, the acceleration time of the separator at the aging temperature was calculated. Thermal accelerated aging tests were then conducted on the separator to complete the production, assembly, and final assembly of the dual-pulse engine separator for positive pressure testing. Ground tests were conducted on the dual-pulse engine separator for positive pressure testing, and the test results were used to determine whether the separator could meet the positive pressure life requirements.

[0047] The specific implementation is as follows:

[0048] (1) Thermal accelerated aging test of interlayer material

[0049] The separator in a dual-pulse solid propellant engine is typically made of rubber. According to research on related materials both domestically and internationally, its aging performance conforms to the Arrhenius equation. Accelerated aging tests on the separator material can be conducted using methods found in GJB10021-2021 "Accelerated Aging Test Method for Composite Solid Propellants" or GB / T3512-2001 "Accelerated Aging and Heat Resistance Test of Vulcanized Rubber or Thermoplastic Rubber in Hot Air".

[0050] Based on the accelerated test of the interlayer material, the aging model of the sensitive parameter of the interlayer material can be obtained, which conforms to formula (1). Usually, the sensitive parameter of the interlayer material is the elongation.

[0051] K = Ze -E / RT (1)

[0052] In the formula:

[0053] K—Aging rate constant;

[0054] Z—Pre-exponential factor;

[0055] E – Aging activation energy (J / mol);

[0056] R—molar gas constant J / (K·mol);

[0057] T—Aging temperature (K);

[0058] Typical engine operating temperature T s Then the interlayer material in T s Lower aging rate constant K s For formula (2)

[0059]

[0060] Generally speaking, the lower the temperature, the closer it is to the mechanism of natural aging. Therefore, while ensuring the time is sufficient, the aging temperature T should be selected. a Then the interlayer material in T a Lower aging rate constant Ka For formula (3)

[0061]

[0062] The interlayer material at aging temperature T a Lower relative operating temperature T s The acceleration coefficient r is given by formula (4).

[0063]

[0064] (2) Calculate the acceleration time of the interlayer

[0065] The engine's estimated lifespan is t years, therefore the lifespan of the separator should be no less than t years. Thus, the separator should be aged at temperature T. a acceleration time t a For formula (5)

[0066]

[0067] (3) Place the partition in a high-temperature insulation box. a The temperature of the insulated box is set to T. a After completing the thermal accelerated aging test of the interlayer, the interlayer is removed.

[0068] (4) Complete Figure 1 The production and assembly of other components besides the partition layer are carried out according to... Figure 1 As shown, the engine assembly for the completed interlayer positive pressure test was carried out. The specific process is as follows:

[0069] First, dummy drug 4 is placed in the test container 3. After the dummy drug 4 has completely solidified, a partition layer 6 is bonded to the top end face and the inner surface of the columnar hollow structure of the dummy drug 4. The transition section 7 and the test container 3 are bolted together. Then, the standard gas generator 8 and the nozzle 9 are connected in sequence by bolts. Subsequently, a pressure sensor is installed on the pressure measuring connector 5. Finally, a single-pulse ignition device 1 and a double-pulse ignition device 2 are installed to carry out the test.

[0070] (5) Conduct a ground test of the engine to carry out a positive pressure test of the interlayer. During the test, the first pulse ignition device 1 works first, spraying out a high temperature and high pressure gas jet to ignite the propellant in the standard gas generator 8. The standard gas generator 8 works until the end. The pressure during the first pulse can be obtained from the pressure measuring hole on the first pulse ignition device 1. The pressure in the second pulse cavity during the first pulse can be obtained from the pressure measuring hole on the second pulse ignition device 2 and the two pressure sensors on the pressure measuring connector 5.

[0071] Comparing the results of the two-pulse pressure with the one-pulse pressure, if there is a situation in the two-pulse pressure that is not much different from the one-pulse pressure, such as a difference of no more than 0.5 MPa, it is considered that the interlayer structure is damaged during the one-pulse operation, and the interlayer cannot meet the positive pressure bearing performance requirements after aging for t years; otherwise, it is considered that the interlayer can meet the positive pressure bearing performance requirements after aging for t years.

[0072] The parts of this invention not described in detail are common knowledge to those skilled in the art.

Claims

1. An accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine's interlayer, characterized in that... include: Thermal accelerated aging tests were conducted on the interlayer material to obtain an aging model of the interlayer material. Calculate at aging temperature T a Below the operating temperature T s The acceleration coefficient r; Based on the estimated lifespan and acceleration factor r, the aging temperature T of the interlayer is calculated. a acceleration time t a ; The interlayer was subjected to accelerated thermal aging test; Completed the positive pressure test of the dual-pulse engine compartment, engine production, component assembly and final assembly; A ground test of the engine was conducted to perform a positive pressure test on the partition of the dual-pulse engine. Based on the test results, it was determined whether the partition could meet the positive pressure life requirements.

2. The accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine partition according to claim 1, characterized in that: The process of conducting accelerated thermal aging tests on the interlayer material to obtain an aging model of the interlayer material is as follows: Based on accelerated testing of the interlayer material, the aging model for obtaining the sensitive parameters of the interlayer material conforms to the following formula, where the sensitive parameter is elongation; K=From -E / RT In the formula: K is the aging rate constant; Z is the pre-exponential factor; E is the aging activation energy; R is the molar gas constant; T is the aging temperature.

3. The accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine partition according to claim 2, characterized in that: The calculation of the acceleration factor at the aging temperature relative to the operating temperature is specifically as follows: Typical engine operating temperature T s Then the interlayer material in T s Lower aging rate constant K s For formula Under the premise of ensuring the time, select aging temperature T. a Then the interlayer material in T a Lower aging rate constant K a For formula The interlayer material at aging temperature T a Lower relative operating temperature T s The acceleration coefficient r is given by the formula 4. The accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine partition according to claim 3, characterized in that: The calculated interlayer at aging temperature T a acceleration time t a Specifically: Assuming the engine's estimated lifespan is t years, and the separator's lifespan should be no less than t years, then the separator at aging temperature T... a acceleration time t a For formula 5. The accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine partition according to claim 1, characterized in that: The partition was subjected to a thermally accelerated aging test, specifically by placing the partition in a high-temperature insulation chamber. a The temperature of the insulated box is set to T. a After completing the thermal accelerated aging test of the interlayer, the interlayer is removed.

6. The accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine partition according to claim 1, characterized in that: The dual-pulse engine partition positive pressure test engine includes: a single-pulse ignition device (1), a double-pulse ignition device (2), a test container (3), a dummy charge (4), a pressure measuring connector (5), a partition (6), a transition section (7), a standard gas generator (8), and a nozzle (9); The cavity inside the test container (3) is filled with dummy drug (4), and a partition layer (6) is bonded to the top end of the dummy drug (4) and the columnar hollow structure on the inner surface of the hole. One end of the transition section (7) is fixed to the test container (3) by bolts, and the partition layer (6) is pressed tightly. The other end is fixedly connected to the standard gas generator (8) by bolts. The standard gas generator (8) is filled with real drug and is used to provide a pressure environment for isolating positive pressure conditions. The nozzle (9) is connected to the standard gas generator (8) by bolts. The first pulse ignition device (1) and the second pulse ignition device (2) are both connected to the test container (3) by threads. During the interlayer margin test, the dummy drug (4) is first placed into the test container (3). After the dummy drug (4) is completely cured, the interlayer (6) is bonded to the top end face and the inner hole surface of the dummy drug (4) in the columnar hollow structure. Then, the transition section (7) and the test container (3) are connected by bolts. Then, the standard gas generator (8) and the nozzle (9) are connected in sequence by bolts. Then, the pressure sensor is installed on the pressure measuring connector (5). Finally, a pulse ignition device (1) and a double pulse ignition device (2) are installed, and the test can be carried out. During the test, the first pulse ignition device (1) works first, spraying out a high-temperature, high-pressure gas jet to ignite the propellant in the standard gas generator (8). The standard gas generator works until the end. The three pressure sensors, namely the pressure measuring hole and the pressure measuring connector (5) on the first pulse ignition device (1) and the second pulse ignition device (2), can determine whether the partition (6) is intact and whether the gas generated by the standard gas generator (8) enters the surface of the fake drug (4) through the partition (6).

7. The accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine partition according to claim 6, characterized in that: The completion of the dual-pulse engine's positive pressure test through the interlayer involves the production, assembly, and final assembly of the engine. First, a fake drug (4) is placed in the test container (3). After the fake drug (4) has completely solidified, a partition layer (6) is bonded to the top end face and the inner surface of the columnar hollow structure of the fake drug (4). The transition section (7) and the test container (3) are bolted together. Then, the standard gas generator (8) and the nozzle (9) are connected in sequence by bolts. Subsequently, a pressure sensor is installed on the pressure measuring connector (5). Finally, a pulse ignition device (1) and a double pulse ignition device (2) are installed to carry out the test.

8. The accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine partition according to claim 1, characterized in that: The aforementioned ground test of the engine undergoing the dual-pulse engine compartment positive pressure test specifically includes: The engine was tested on the ground during the positive pressure test of the interlayer. During the test, the first pulse ignition device (1) worked first, spraying out a high temperature and high pressure gas jet to ignite the propellant in the standard gas generator (8). The standard gas generator (8) worked until the end. The pressure during the first pulse operation can be obtained from the pressure measuring hole on the first pulse ignition device (1). The pressure in the second pulse cavity during the first pulse operation can be obtained from the pressure measuring hole on the second pulse ignition device (2) and the two pressure sensors on the pressure measuring connector (5).

9. The accelerated aging test method for assessing the positive pressure bearing life of a dual-pulse engine partition according to claim 8, characterized in that: Comparing the results of the two-pulse pressure and the one-pulse pressure, if there is a situation in the two-pulse pressure that is not much different from the one-pulse pressure, that is, the difference does not exceed 0.5MPa, then it is considered that the interlayer structure is damaged during the one-pulse operation, and the interlayer cannot meet the positive pressure bearing performance requirements after aging for t years; otherwise, it is considered that the interlayer can meet the positive pressure bearing performance requirements after aging for t years.

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